The window sash and method of construction disclosed in U.S. Pat. No. 3,803,779 to Kuyper et al. is representative of the prior art to which this invention is an improvement. Previously a strip of tape would be placed over the groove and the glazing would then be inserted into the groove causing the tape to shape itself around the glazing on opposite sides. The tape would then need to be trimmed away with a blade as seen in FIGS. 13 and 14 of the present disclosure.
Other problems associated with using silicone in groove glazing includes handling. The silicone must have one to six hours to cure. Clean up is a problem since once silicone gets on the glass it is nearly impossible to remove it.